The story of Charles E. Moritz v. Commissioner of Internal Revenue, from 1972, the only case that Martin Ginsburg argued alongside his wife Ruth Bader Ginsburg. Their client was an unmarried salesman taking care of his elderly mother, but the tax code prohibited him from deducting caregiving expenses, because he was a man. The attorneys, working with the A.C.L.U., thought that a male plaintiff would be the perfect vehicle for a gender-discrimination case. They were right: the Tenth Circuit ruled in their favor.